Method of recovering ammonia in the cuprammonium cellulose precipitation.



UNlTED STATES PATENT OFFICE.

EMILE BRONNERT, OF NIEDERMORSCHWEILER, GERMANY, ASSIGNOR TO VEREINiGTE GLANZSTOFF-FABRIKEN A. G.. OF ELBERFELD. GERMANY.

METHOD OF RECOVERING AMMONIA IN THE CUPRAMMONIUM CELLULOSE PRECIPI- TATION.

No Drawing.

7' (1/! whom. it ilm concern.

lic it known that l. lliuna-i linoxxiarr, a subjcct ol' the (lei-man Emperor. residing at .\'icdcrmorschwcilcr, Germany. have inrcnlcd certain new and useful improve ments in the ethod trfxlitilizing Cellulose \Vash lliqu rs from the tupramnioniaProcess, of which the F ollo\\"in,g is a specification.

\Vhcu subjecting to precipitation. solutions of cellulose in cuprammonia, for the production of artificial articles, and espe- ('l:|ll when this is done with alkaline ae'cuts. according to the recently developed practice. the ammonia which is no longer rcquii-cd as a solvent, will escape. llerctot'orc this ammonia has bccn withdrawn by enhaustcr:- or fans at the placc of formation and then absorbed by sulfuric acid. This method involves on the one hand a rather (:onsidcrablc consumption of sulfuric acid, and on the other hand a further consumplion ol 'quieklime or the like in order to lihcratc thc. absorbed ammonia and render it. arailable tor rcucwcd use in the operation. it is obvious that the. considerable amounts of gypsum produced during this treatment are a cmnbcrsome and expensive waste product of the manufacture.

l have discovered that a great improveuu-nt is achieved if instead of sulfuric acid wiuse the aqueous waste liquors resulting from the washing process. Now if these \Yusli liquors are caused to llow down in a lower ulu-rcin they are met by an upward current of air containing ammonia, the latfor is absorbed and will form coppcrammoniawomhinations. if this liquid is then caused to travel in contact with an oppoiteli flowing current of steam in a column apparatus of \reltlinown character, the amlnonia will be expcllcd and may be absorbed by water and returned to the cycle of op crations. This operation will be used for all wash liquor whcthcr alkaline or acid liquors. The method however acquires iner iscd prartiral value when alkaline precipitating agents arc employed, for instance caustic soda lye containing sugar. During the subsequent washing of the threads with water the adhering soda or the soda previously combined with the molceule of (tupracellulose is dissolved, and there is further dissolved, with the assistance of Specification of Letters Iatent.

Patented Apr. 16, 1912.

Application filed January 17, 1911. Serial No. 603,094.

monia from the lycs of cuprammonium sulfate. with the addition of further amounts of alkalis. if necessary.

in using acid wash liquors, which contain copper sulfate, etc, firstly ammonia acts as a neutralizing agent and further combines with the copper sulfate forming cuprarumouium-sutfate. The combining power of the wash liquors may be further increased by adding to them any suitable salts 5 calcium chlorid) able to form double compounds containing ammonia. But the procccdiug is the same. as described with reference to alkaline wash-liquors.

I claim as my invention 1. The method of recovering from air ammonia set free in the precipitation of cellulose from a solution of cellulose in cuprammonium, which consists in passin said ammonia-bearing air in contact with liquor in which said cellulose-precipitate has been washed. and again separating the ammonia from said liquor.

2. The method of recovering from air ammonia. set free in the percipitution of cel lulose from a solution of cellulose in cuprammonium, which consists in passing said ammoniabcaring air in.contact with alkaline liquor in which said cellulose-precipitate has been washed. and again separating the ammonia from said liquor.

I l. The method of recovering from air ammonia set free in the precipitation of cellulose from a solution of cellulose in cuprammonhuu. which consists in passing said ammoniatearing air in contact with liquor in which said ttlllllt prccipitatc has been washed, and hcatiue said liquor to expel the ammonia.

4. The method of recovering from air amthe sugar, a certain portion of the copper, monia sci fn-e in the precipitation of col- IOU liquor.

lulose from a solution of cellulose in on prammonium, which consists in passirr said unnnoniwbea-ringeir iii oontecfc' witl in which said cclluiose-pretaipitate hes Been washed containing copper again separating the ammonia from said The method of recovering from air ammonia set free in the pg ecipitation of cellulose. Vfro n a! Solution hello-lose in cuprammoni iim, which consistaimpassing said ammonia-bearing air in oonla't with liquor in which said cellulose-prod. 'itatehas been washed, ('0 which have been added sub stances having an aflinibyxfor ammonia, and again. separating lhe nminonia from said liquor.

6. The method ,of utilizing Wa,sh liquors employed; in the manufncturmg of ce1l\1-.

lose precipitates from a solution of celh-Ydroxid, and

lnlose in cuprannnonium,which consists in passing said liquors in contact with a stream Jgnm; of ammoniarbearing nirywhereby said ammonia is absorbed by said liquors.

7. The method of utilizing alkaline wash liquors containing coppenhydroxid in 5115- pension employed in the manufacturing of cellulose precipitates from a solution of cellulose in cuprmmnonium, which consists in passing said liquors in contact with a stream of ammonia-hearing air, whereby said ammonia absorbed by said liquors.

In Witness whereof, I have hereunto signed my name in lh presence of two subscribing witnessesv EMiLE BRONNERT.

\Vitnesses Joscen NlTLLARI), \V. J. MERTEN. 

